110 Missouri Agricultural Report. 



slaughtered to obtain blood for experimental purposes. The au- 

 topsy notes are very much like those reported above, except that 

 the spleen was more enlarged and the lungs showed a slight in- 

 filtration at the inferior borders of the anterior lobes. November 

 30 the third non-vaccinated sow died; this was the sow that had 

 aborted. 



The three vaccinated hogs that showed no signs of the disease 

 were thus continuously exposed for twenty-six days or more in 

 very close contact with the hogs suffering from the disease. These 

 and the two recovered pigs were further exposed by putting with 

 them December 9th a sick pig from an outside pen. This pig re- 

 covered after a prolonged illness. In the meantime it had doubt- 

 less added considerable infectious material to the pen. No harm 

 came to the vaccinated pigs from this additional exposure. 



January 24th one of the recovered pigs and one that had never 

 shown any symptoms of cholera, in lot 4, were fed viscera (spleen, 

 liver, intestines and kidneys) obtained from hogs that had died 

 from cholera in a herd suffering from a natural outbreak of the 

 disease, and in which both the hog cholera and swine plague types 

 were present. 



The two pigs that were fed the viscera suffered no ill effects, 

 nor did the other vaccinated pigs of the same lot that were exposed. 



In lot 4 it will be seen that only one of the six vaccinated hogs 

 died, and three showed no illness, while five non-vaccinated hogs of 

 the same breeding that were inoculated or exposed to the same in- 

 fection died. It therefore seems that the serum used in this case 

 had some power to protect against the disease. Its potency, how- 

 ever, was not as great as the serum obtained from supply animals 

 made "hyper-immune" by hypodermic injection of a large amount 

 of infectious blood, as is shown by comparison of lot 4 with lots 

 1, 2 and 3. In the last named lots of 24 pigs only one showed any 

 signs of sickness. This one in lot No. 1, died after a very linger- 

 ing illness. A large abscess had developed under the throat. While 

 the symptoms indicated a case of cholera, the post-mortem in this 

 animal gave no clear evidence that the death was caused by this 

 disease. The non-vaccinated animals in these lots, with the excep- 

 tion of one check pig in lot 1, died from the disease. This one at 

 no time showed the slightest illness. The reason for this resist- 

 ance of the non-vaccinated pig I am unable to explain. Such oc- 

 currences, however, are observed in natural outbreaks of the dis- 

 ease. I think it very probable that the check animals which died 

 in pen 1 and 2 contracted the disease from infection carried into 



